Cleaning appliance for attachment to a vacuum cleaner



April 9, 1968 H. WESSEL 3,376,598

CLEANING APPLIANCE FOR ATTACHMENT TO A VACUUM CLEANER Filed March 5, 1965 4 Sheets-Sheet 1 Hans Wessel By To 5 Jam April 9, 1968- H. WESSEL ,3

CLEANING APPLIANCE FOR ATTACHMENT TO A VACUUM CLEANER Filed March 5, 1965 4 Sheets-Sheet 2 I l I 33 W 56 i 3 40 A mum/r029.- 57 Hans Wesse/ To 6 Jabm H. WESSEL April 9, 1968 CLEANING APPLIANCE FOR ATTACHMENT TO A VACUUM CLEANER 4 Sheets-Sheet 5 Filed March 5, 1965 FIG. 74

FIG. 15

mus/wo Hans Wessel 89 m & Jfahm A ril 9, 1968 H. WESSEL CLEANING APPLIANCE FOR ATTACHMENT TO A VACUUM CLEANER 4 Sheets-Sheet 4 Filed March 5, 1965 mus/v rap.- Hans Wesse/ By 20:: 6' Jbslem 3,376,598 Patented Apr. 9, 1968 CLEANING APPLIANCE FOR ATTACHMENT TO A VACUUM CLEANER Hans Wessel, 5225, Wildbergerhutte, Bezirk, Cologne, Germany Filed Mar. 5, 1965, Ser. No. 437,388

Claims priority, application Germany, Oct. 8, 1964,

W 37,703 5 Claims. (Cl. -382) This application is a continuation-in-part of my copending application Ser. No. 360,335 filed Apr. 16, 1964 and now US. patent No. 3,235,899 granted Feb. 22, 1966.

The invention relates to an improvement in and a further development of the subject matter disclosed and claimed in this patent. The subject-matter of the patent is a cleaning appliance which can be connected to a vacuum cleaner, and which has devices which make it a universal cleaning appliance selectively usable for beating carpets and for brushing or vacuum-cleaning carpets and floors.

For this purpose, the underside of the appliance is equipped with brush bars which may be recessed in the interior of the housing, rotatable brush rollers and beater bars vibrated by the suction-induced air current, and also a suction nozzle, wherein, by the selective switching of some of these elements, either the beating means or the suction means is used.

The improvement and further development of the subject-matter of the patent consists in that instead of the two brush rollers on the underside of the cleaning appliance, one or more combs are mounted in recesses or slots in the vacuum-cleaner housing which take over the task of rotatable brush rollers.

In the practical realizations of this universal cleaning appliance it has been seen that by the beating action alone, the carpet which is to be cleaned is not satisfactorily vacuumed free of dirt, particularly threads, fibers and like textile elements, and accordingly in the patented system brush rollers have been provided which are rotatably and loosely disposed and are assigned the task of loosening such fibers and pulling them out of the carpet as the appliance rolls over the carpet, so that on subsequent beating and suction action remove the fibers to a substantial extent.

With these brush rollers it is possibe for the loosened threads to adhere to the bristles of the brush rollers or in particularly unfortunate cases to wind round the brush rollers and becomes fixed, with the result that blockage,

jamming or even stoppage of the rollers can arise, in r the course of time. The brush rollers indeed can be cleaned manually, but this is very inconvenient, as the person using the apparatus is forced to pick off the separate threads.

The comb used instead of the rollers is advantageously toothed on the side turned towards the carpet, or may be saw-tooth edged, but preferably has a wavy contour. It consists of elastic material (e.g. such as that marketed under the name Vulkollan) and can be adjusted in height inside the slot.

In particular, the comb is resiliently carried in the slot in such a way that under a determined, preferably slight pressure as the appliance rests on the carpet, the comb is pressed onto the same so that with the to and fro movements of the appliance over the carpet the projecting serrated edge of this comb loosens up any threads that there are in the carpet, takes hold of them and causes them to set upright so that they are in a position in which, by the subsequent beating and the suction opera- F tion, they are drawn from the carpet.

A further improvement, in accordance with the pres ent invention, resides in the particular shape and positioning of the beating bars consisting of elastic bands.

It has been found that on occasion on the coincidence of certain elements influencing the vibration of the elastic bands, the said bands, on vibrating heavily, are held tightly by the suction force of the suction air current onto the suction slit of the suction channel located above the bands, and remain fixed on this slit, so that thereby the beating effect is made inoperative. This disadvantageous effect can, it is true, be overcome by switching off the vacuum cleaner for a short time, so that the suction effect is broken otf andthe elastic bands are released from the suction slit and return to their original flat position; the trouble can be repeated in certain circumstances and can lead frequently to some interruption of the cleaning process.

Apparently this phenomenon of the fixing of the separate elastic bands is ascribable to the fact that-possibly quite by chance or because of the coincidence of certain vibration c0nditionsthe bands vibrate synchronously, even if only at a quite determined point of time, and, moreover, have the same amplitude, so that all the bands to a certain extent act like a single broad strip and are sucked into the suction slit by the air current.

To overcome these disadvantages, the present invention provides that the separate bands are manufactured of material of various elastic strengths, that is to say some bands are less strongly elastic than others, and as a result the vibrating properties, as far as concerns vibration number, phase and amplitude, are different so that the above-mentioned phase and amplitude synchronisation is not very likely.

A further solution offered by the invention is to manufacture the separate bands of the same elasti material, of the same elasticity and yielding strength, but so to adjust them to each other in their length in unclamped uninstalled state that on the taking up of a stretched position by one, two or several bands, other bands sag a little because of their greater length. When the bundle of bands is installed in the appliance and stretched somewhat, even the bands which in unclamped stage sag somewhat are a little more stretched, but on installation they still, in accordance with the degree of stretching, either remain slightly sagging or all bands will take up a parallel fully extended position. However, as some of the bands are more strongly tensioned, others-i.e. the bands which even the bands which in unclamped state sag somewhat. less tensioning, and the separate bands will not only have diiierent phase characteristics but also different vibration width or amplitude; accordingly the danger of all the bands becoming fixed in the suction slit by the suction eifect is reduced.

The invention provides finally the further possibility of preventing the blocking of the bands by suction, by disposing On both sides of the suction slit located above the bands, bosses, ribs, shoulders and projections of this nature, so that of the bands, one, or a few bands collectively, come to rest on the support during vibration. By this means on the arising of synchronisation of phase and amplitude, to a certain extent the blocking of the mouth of the suction slit is avoided. The bands in this maximum vibration state, i.e., maximum amplitude, are spaced from each other so that there is sufficient space between the separate bands for the air to enter, and the locking by suction elfect of the bands is thereby avoided. It is of inventive significance here that, all the same time, the beating effect is intensified, because on account of the diiferent tensionings or elasticities in the beating bars and because of the bosses, webs and shoulders for the abutting of separate bands, the amplitude becomes still greater than with the elastic bands of the main patent. Thus, with one and the same measure, the double advantage is obtained of preventing the jamming of the suction slit and thereby preventing an interruption of the beating effect on the one hand, and on the other hand there is the advantage of an increase in the beating effect.

In a further development of the inventive idea, at the clamp supports of the elastic bands in the housing of the apparatus, either for one or several of the elastic bars, projections can be provided, which at the clamp bearings are directed to run straight and/or obliquely or offset, in particular inwardly towards the suction slit, the said projections having the task of pressing the appurtenant elastic band out of the plane of the other bands, and preferably inwardly. The said projections, which are constructed as extensions of the clamp element and on the midbeating bar are directed inwardly towards the suction slit, have the task of preventing a full stroke of the central beating bar between the two outer bars. As

the bars lie advantageously close to each other, full stroke vibration of the central band could cause functional disturbance by mutual jamming of the bars.

In another embodiment of the invention it can be advantageous on clamping the bands in the support clamps, to install first the two outer bars, and only then the midbar, here care being taken that the sum of the width of the three bars is greater than the internal width of the support clamp. By this means it is possible to ensure that the contact surfaces of the bars are of trapezoidal cross-sectional obliquely running flattened configurations upon deformation of the elastic bars, of such a nature that the mid-bar over against the outer bars can only vibrate such that it vibrates-through inwardly onto the suction slit, but not, however, outwardly between the two outer bars.

By reason of the fact that the sum of the widths of the three bars is greater than the internal width of the clamp bearing or of the vibrating space, the longitudinal edges of the bars are overlapped and the consequence of this is that on the vibrating movements the outer edges of the mid-bar in the overlapping region strike on the inner longitudinal edges of the outer bars and thereby prevent not only a vibrating-through of the midbar outwardly prevented by the outer bars, but also during the periods during which the overlapping parts come to rest in mutual contact, the air-flow through the three bars is temporarily cut-off, so that a strong suction of the bar arises because any reduction of intensity is prevented by auxiliary air. In this way an intensive beating movement of the bars is obtained.

According to another feature of the invention I provide bosses, rib shoulders, projections or the like shoulders on the base of the suction channel within which the elastic bands vibrate; in the cleaning housing said projections, viewed in the longitudinal direction, are asymmetric (i.e. staggered diagonally with respect to each other on both sides of the suction slit). They are disposed such that on the vibrating-through of the elastic bars, an asymmetric contact with the respective shoulder takes place, with the result that the vibrations have an asymmetrical vibration configuration in relation to the midline of the appertinent clamp bearing, which, moreover, in reference to the separate bars is different in each phase.

The improvement provided by the inventive idea gives great security against the fixing by suction effect observed with known brushes, and moreover increases the beating effect, because by the asymmetrical abutting of the outer bars on the bosses a displacement of the amplitude is obtained and thereby at the same time an extension of the beating surface.

It can be adavntageous to construct the cleaning appliance as a beating nozzle for padded furniture, operated by hand, and to install on the underside the elastic beater bars, as in this way the apparatus is given a slim the attached drawings which are given in no restrictive.

sense, and which show several embodiments of the invention.

FIGURE 1 is a view of the underside of a cleaning appliance according to the invention.

FIGURE 2 is a front elevation of the carpet treating comb in part section along the line lI-II of FIGURE 1.

FIGURE 3 is a side elevation of the bundle of bars in untensioned state, with different lengths of the individual bars FIGURE 4 is a similar side elevation, but in the tensioned state of the bundle of bars;

FIGURE 5 is a longitudinal section through the appliance along the line VV of FIGURE 1 in accordance with another embodiment of the invention, in which hearing webs are provided on both sides of the suction slit.

FIGURE 6 is a part cross-section along the line VIVI of FIGURE 1.

FIGURE 7 is a part bottom view of the appliance in the region of the elastic bars after installation of the said bars.

FIGURE 8 is a longitudinal view similar to FIGURE 5, but with bearing shoulders for the elastic bars instead of the webs.

FIGURE 9 is a part bottom view seen from underneath,

the cleaning appliance in the region of one clamp bearing of the elastic bars.

FIGURE 10 is a part cross-section through the clamp bearing and the mid-elastic bar in section along the line X-X of FIGURE 9.

FIGURE 11 is a part view from underneath of the cleaning appliance in the region of the suction slit with asymmetrical shoulders.

FIGURE 12 is a part crosssection through the appliance in the embodiment of FIGURE 11, along the line XII-XII.

FIGURE 13 is a diagrammatic representation of the various vibration configurations.

FIGURE 14 is a bottom view of a hand beating nozzle, in particular for cleaning padded furniture after the removal of the beating bars.

FIGURE 15 is a bottom view similar to that of FIG- URE 14, but when the beating bars have been installed.

FIGURE 16 is a longitudinal section through the heating nozzle along the line XVI-XVI of FIGURE 14.

FIGURE 17 is a cross-section through the hand heating nozzle in accordance with the line XVII-XVII of FIGURE 15.

FIGURE 18 is a similar cross-section through a hand beating nozzle with flexible pipes disposed in longitudinal slots in place of the brush bars.

FIGURE 19 is a part longitudinal section through the beating nozzle with saw-tooth like engagement of the elastic heating elements.

In accordance with the embodiment of FIGURES l and 2, as described in my copending application, now patented, a comb 1 consisting of polyurethane is installed in an easily yieldable slot 2 of thehousing 3 of the clean ing appliance. The slight arching of the slot 2 is for the,

purpose of ensuring that by the scratching or scraping action on the separate threads, they are better put in the way of the beater bars 4.

The scraper comb has undulations 6 on the outside edge 5, and also separate hooks 7 by which it is hooked onto the interior of the appliance behind shoulders. Fur-,

thermore, in the vicinity of the two end regions, by fiat triangular openings 8, flat angular springy parts 9 are formed,

with the pointed teeth of which the comb abuts on the base 11 of housing, In untensioned state the comb 1 projects by an extent shown at 12 out beyond the slot 2 of the appliance housing 3. When the appliance is set on the carpet, the distance 12 is reduced by the pressing effect of the carpet fibers, and the comb is partly pressed back into the interior of the housing, this being possible because the springy parts 9 of the comb are deformable and take up a position something similar to that shown in broken lines in FIGURE 2.

By the undulate shape of the outer edge on the one hand, and the easy deformability of the comb on the other, the carpet in being treated in this way is not only protected but care is moreover taken that the threads, simply because of this protective treatment, due to the light pressure, are better loosened from the carpet and made to stand on end than was the case with the previously used brush rollers. The advantage of the comb of the invention furthermore consists in that it does not have to be subsequently cleaned, as was the case with the brush rollers,

as no hairs or threads or other dirt can adhere to the comb.

The two outer bars of the elastic bars 4 as can be seen in FIGURE 3, are, in their untensioned state, shorter than the middle band 13, so that in the stretched condition of the outer bars 4 this central bar sags a little. When the bars with their clamps 14 are installed in the suction channel 16 of the appliance housing 3 they have to be stretched for this purpose, as FIGURE 4 shows by the arrow 15, and by this action the central bar shown in dotted lines in FIGURE 4 straightens itself out a little from the hanging down position of FIGURE 3, so that the sagging is now very slight. This position in the mid-region can be seen in the cross-section of FIGURE 4.

In the embodiment of FIGURES 5 to 7, on both sides of the suction channel 17 disposed underneath the bars there are provided bosses 19 on the base 18 of the suction channel 16 of height and width such that only the two outer bars 20 come to rest on them above on vibrating, thereby being restricted in amplitude above, whereas the middle elastic bar 21 can vibrate unimpeded with greater amplitude between the two bosses 19. This ensures that on unfavourable conditions arising, two, or even all the bars simultaneously, shall not vibrate up into the suction slit 22 and completely block this opening, remaining sucked in it.

With the embodiment of the bosses it is not essential to have differing elasticity for the separate bars; on the contrary all three bars can be manufactured of equally elastic material and can have the same length when extended, so that in the tensioned state also the three bars have the same inner tension, and even so it is possible very effectively to prevent the suction blockage of the slot, by the arrangement of the shoulders.

It is expedient in accordance with the invention for reasons of adjustment possibilities to adjust the heights of the bosses 19 as indicated by the double-arrow 23; furthermore the clamps 14 can be of adjustable height in the suction channel 16 of the housing 3 in accordance with the double-arrow 24 and as a result of this the part 26 of the bands projecting over the underedge 25 can, upon vibration of the elastic bars, be adjusted and accordingly the beating effect also.

FIGURE 8 shows that the projecting part 26 of the bars can be made larger if the clamps 14 are pushed in nearer to the underedge 25 of the housing, this being done by means of the adjusting screw 27.

Instead of the bosses 19, the recess 28 for the bars 20 and 21 on both sides of the central suction opening 32 can have stepped shoulders by this means, in a way similar to that achieved with the bosses 19, some of the elastic bars are restricted in amplitude whereas others can vibrate up to the mouth of the suction opening 32. This possible embodiment affords a wider contact surface in the restricting of the amplitude; the surfaces are shown in FIGURE 8 by the arrow 31.

It has been found that with the arrangement of the elastic bars as heating elements, in particular for carpets and padding, there easily arises a jamming of the elastic bars at the suction opening on the vibrating-through of the bars with the result that the beating efiect ceases. For overcoming t'his disadvantage, practical tests have shown that it is sufiicient, in accordance with the embodiments of FIGURES 9 and 10, to give the clamp 34 a special shape, in that the U-shaped clamp 41 can have an angled nose or tongue 42, the aim of which is to offset the central bar 40 towards the suction slit as can be seen in FIG- URE 10. By this means practically over the whole free length the central bar 40 is pressed on the suction slit at a level 33 compared to the two outer bars 39. The three bars can accordingly be of the same rubber material and can be so dimensioned in respect of each other that in spite of the offsetting of the central bar and thereby the increase in its total length, in all bands the same tension prevails in the tensioned state.

With three bars of exactly the same material composition these bars can also, however, be given originally the same tension length so that in final tensioned state, because of the olfset by the protection, the central bar has a greater pretensioning than the two outer bars. This has the advantage that the vibrations are asynchronous and the danger of jamming at the suction slit is avoided. This construction in accordance with the invention has the advantage that in the final state, beating bars are obtained, the middle one of which is pressed against the suction opening, although at the clamp bearing in the vicinity in the clamp 41 all three bars are at the same height and thereby in alignment with each other, where-by a simplification of production is made possible, in that a smooth cover plate or bar 43 and three identical hollow rivets 44 can be used.

It is advantageous for the central bar to be pressed inwardly by the projections, so that undesired vibratingthrough of this central bar into an outer position in which the central bar would project outwardly out of alignment from the adjacent bars is avoided.

It can be advantageous to make the sum of the three widths 55, 56 and 57 of the three bars somewhat greater than the internal width 58 of the U-clamp, by an amount which is adequate in order to close the two gaps which arise at any time between the central bar 40 and the two outer bars 39 by reason of the offsetting of the central bar by the projection 42. If one makes the sum of the widths 55, 56 and 57 of the three bars equal to the internal width 58 of the U-clamp, gaps 59 would arise through which on the suction process air can pass, so that the vibrating process is impaired.

In accordance with the embodiment of FIGURE 18 a further step forward is more in this direction, and the internal width of the Uclamp 41 is made substantially smaller than the sum of the widths of the three bars, so that on clamping a considerable deformation of the bars arises at the particular clamping place, because here the bars are crushed into trapeze-configuration; by this one achieves that directly at the outlet place the three bars in non-deformed state lie against each other at the longitudinal sides. Here care must be taken furthermore that first the outside bars are installed adjacently in the U- clamp 41 of the clamp bearing 34 at the arms 60, and only then the central bar. If one now, by means of the cover sheet 43, presses the three bar ends together, then one obtains the configuration of the 'bars in accordance with FIGURE 18, and only at the clamp bearing, whereby obliquely-running trapeze-shaped surfaces 44 occur, which are the reason why the central bar 66, directly outside the outlet from the clamp 34, lies adjacent on the sides 61 as in FIGURE 17, whereby the compact closure of all bands in relation to each other is obtained, which again has the advantage that the vibrating-through of the central bar outwardly is thereby avoided.

In accordance with the embodiment of FIGURES l1 to 13, the bosses 35 and 36 for the two outer bars 39 are each disposed outside the arrow sides of the suction slit 37 alternatingly in such a way that the outer-lying bars 39 execute asymmetric vibrations in relation to the midpoint, 13, whereas the other bar 39 executes the vibration 50 shown in dot/dash lines, because it strikes against the other nose 47. The greatest amplitude at any time are at any time spaced in time from each other by about a third of the total clamp length of the bar. In this way compared with the previous embodiment with two shoulders in accordance with the dotted representation of FIGURE 13, with the two outer rubber bands on two noses 47 and 49 coming to rest, a substantially lesser amplitude arises, and moreover it runs practically symmetrically to the midpoint.

In the arrangement of a single boss displaced diagonally from the middle outwardly, the amplitude of the vibration at any time is particularly great, for two reasons; on the one hand the vibrating-through at the zone of maximum amplitude is particularly great because there no loss is in the way, and on the other the out-stroke is particularly great due to the vibration taking place over a much greater free length (52 and 53) than with the arrangement with two bosses.

From FIGURE 13 it can be seen how the bar can swing up in the direction of the suction slit, by omitting one boss at the place concerned, to the height of the said boss for example 47. A further advantage of the asymmetric vibrating-through consists in that no synchronous vibrations in phase and in amplitude can arise between the separate bars, such as are frequently the cause for the common jamming of all the bars at the suction slit.

In accordance with the embodiment of FIGURES 14 to 17 the beater bars are to be of elastic material and with a hand-operated beating nozzle for padded furniture, which can be connected to the suction line. This device has three beater bars 66, which are clamped in the clamp bearing 67. In order to keep as low as possible the air resistance inside the suction channels, the suction slit 68, in the direction towards the handling connecting piece 69, can be displaced on one side by the extent 70 from the mid-line 71; the appliance is grapsed by hand in the region of the suction connecting piece 69.

On both sides of the beating bars 66 brush bars 79 which can sink into the housing can be provided.

The housing 91 is divided into two chambers 93 and 94, the lower chamber 94 being constructed as a longitudinal box, open downwardly, which by means of a midopening or slit 68 provided in the intermediate wall 95,

passes upwardly into the housing part 93 which is constructed as suction channel and is in connection with the connecting piece 69.

In the lower housing-part 94 there are three vibrating elements 66 which consist of elastic or springy material and are carried in clamp bearings 67. At the intermediate wall 95 the bosses 87 are provided for restricted contact with the bar 66.

The lower housing-part 94 in the vicinity of the lower surface 97 is provided with expanded edge parts 77, in which in the longitudinal direction slots 80 are provided for the reception of bars 79 which carry brush elements 78. So that the bars 79 can be removable and yet firmly inserted, there are provided, parallel to the slots 80, further slots 85 so that spring elements 81 arise; the latter are provided with hooks 82 behind which the upper edge of the separate bars 79 can be snapped in.

It is advantageous to use as material for the nozzle housing a resilient or elastic plastic, and furthermore to construct the spring elements 81, looked at lengthwise, as short spring-elements, constructed in such a way that transverse slots 83 are provided, the hooks 82 being disposed only on these short spring elements 81. Therebetween there are comparatively long intermediate walls 84, which have a distance from the associated outer wall 97 which is somewhat wider than the width, at the time 8 concerned of the brush bars 79. In this way the brush bars can be made to engage easily in the slot with springy yielding of the three spring elements 81.

The middle beater bar can be sucked in up to the intermediate wall 95, so that between the mid-beater bar on the one hand and the two outer beater bars on the other hand, during the suction process there is a gap through which air is sucked. With the given dimensions the suction process is repeated at approximately 2,000 to 2,500 times a minute, whereby all three bars are swung up out of their clamped position.

In the embodiment shown in FIGURE 18, in the place of the brush bars in the two longitudinal slots 8 a hose 100 is inserted, of flexible elastic material, preferably polyurethane. By the springy equalizing property of the hose, rough paths in the working surfaces and also deepseated unevenness are bridged, over, and by the straightening efiect of the surface of the hose arising thereby, threads and fibers are loosened from the surface and sucked up by the suction current. The beater nozzle for padding of the invention has the further advantage that the heating element can easily be removed from the hearing points so that in case of need the appliance can be used as a pure suction nozzle.

For this purpose in accordance with FIGURE 15 at one of the clamp bearings 101 a loop is provided which gives a good hand-hold. The clamps provided at both ends of the beating elements are carried in grooves 103 of the housing. On the installing of the beating element, one end is hooked on with the clamp 96 into a rear-cutting 104, and then by the loop 102, the other end of the heating element is inserted by mean-s of the other clamp 101into the other groove.

In order to adapt the heating element driven by the suction air current to the suction capacity of the vacuum cleaner, some beating bars can be clamped or held more strongly than others. For this purpose, at one groove for one end of the heating element at the base of the said groove, saw-tooth notches 105, as in FIGURE 19,

are provided with rear-cutting 106, into which a corresponding raised part 107 outhe clamp bearing 108 of the beating element can be made to engage.

In FIGURE 19 the mid-engagement place is indicated. As a result of the rear-cutting 106 it is ensured that the clamp bearing 108 cannot spring out of the saw-tooth notching. From this one can seethat it is important to give the beating element a certain pre-tensioning, also in the weakest clamp position.

I claim:

1. In a vacuum-cleaner head for the pickup of loose materials from the surface, said head having a housing provided with an elongated recess open in the direction of said surface, duct means in said housing communicating at an opening with said recess at a location therealong for applying suction to said recess, and a plurality of longitudinally extending laterally continguous independently oscillata'ble resilient beater bands spanningthe mouth of said recess and vibratable in respective planes into and out of said recess upon the induced flowof air inwardly into said recess upon the application of suction thereto, to beat against said surface and loosen said materials thereon, the improvement which comprises:

at least one formation upstanding from the fioor of said recess alongside said opening for asymmetric engagement with a respective beater band with respect to a plane perpendicular to said bands and through said location, whereby at least one of said bands is intercepted asymmetrically upon its movement toward the floor of said recess during vibration thereof, thereby imparting an asymmetrical waveform to said one of said bands and an out-of-phase movement to them into and out of said recess; and fastening means at the opposite end of said recess for securing the corresponding extremities of said bands to said housing with said extremities lying substan- 10 tially in a common plane parallel to said surface, of said recess in the direction of said one end of said three beater bands being provided within said recess housing. and the mouth of said recess has substantially a width 4. The improvement defined in claim 3 wherein said at most equal to the combined widths of said bands, housing has marginal portions surrounding said recess said bands including a pair of outer bands and a cen- 5 and forming a supporting surface for said housing, said tral band disposed between said outer bands, said handle means having a width approximating that of said formation being engageable with one of said outer recess for engagement by the hand of the operator. bands, said fastening means being provided with a 5. The improvement defined in claim 1 wherein only a deflecting member at each extremity of said central single formation is provided for engagement with one of band for retaining said central band in a mean posi- 10 said outer bands. tion thereof above said outer hands over substan- References Cited tiallythe entire length of said central band. UNITED STATES PATENTS 2. The improvement defined in claim 1, wherein said fastening means includes a backing plate at each end of 2314O81 3/1943 DOW et 15402 XR said recess and a respective clamping plate sandwiching 15 61 11/1958 KuPpersmlth 15 382 the extremities of said bands between said backing plate 3002'217 10/1961 smlthson et 15*382 and said clamping plate, said clamping plates having in- 3235899 2/1966 Wessel 15 382 XR wardly bent fingers constituting said members. FOREIGN PATENTS 3 The improvement defined in claim 1 wherein said housing is a hand-held cleaning head provided with handle 20 great Britain reat Britaln. means aligned with said recess, said duct means passing 910,697 11/1962 Great Britain through said handle means and communicating with said recess at a location offset from the longitudinal center ROBERT MITCHELL, Primary Examiner- 

1. IN A VACUUM-CLEANER HEAD FOR THE PICKUP OF LOOSE MATERIALS FROM THE SURFACE, SAID HEAD HAVING A HOUSING PROVIDED WITH AN ELONGATED RECESS OPEN IN THE DIRECTION OF SAID SURFACE, DUCT MEANS IN SAID HOUSING COMMUNICATING AT AN OPENING WITH SAID RECESS AT A LOCATION THEREALONG FOR APPLYING SUCTION TO SAID RECESS, AND A PLURALITY OF LONGITUDINALLY EXTENDING LATERALLY CONTINGUOUS INDEPENDENTLY OSCILLATABLE RESILIENT BEATER BANDS SPANNING THE MOUTH OF SAID RECESS AND VIBRATABLE IN RESPECTIVE PLANES INTO AND OUT OF SAID RECESS UPON THE INDUCED FLOW OF AIR INWARDLY INTO SAID RECESS UPON THE APPLICATION OF SUCTION THERETO, TO BEAT AGAINST SAID SURFACE AND LOOSEN SAID MATERIALS THEREON, THE IMPROVEMENT WHICH COMPRISES: AT LEAST ONE FORMATION UPSTANDING FROM THE FLOOR OF SAID RECESS ALONGSIDE SAID OPENING FOR ASYMMETRIC ENGAGEMENT WITH A RESPECTIVE BEATER BAND WITH RESPECT TO A PLANE PERPENDICULAR TO SAID BANDS AND THROUGH SAID LOCATION, WHEREBY AT LEAST ONE OF SAID BANDS IS INTERCEPTED ASYMMETRICALLY UPON ITS MOVEMENT TOWARD THE FLOOR OF SAID RECESS DURING VIBRATION THEREOF, THEREBY IMPARTING AN ASYMMETRICAL WAVEFORM TO SAID ONE OF SAID BANDS AND AN OUT-OF-PHASE MOVEMENT TO THEM INTO AND OUT OF SAID RECESS; AND FASTENING MEANS AT THE OPPOSITE END OF SAID RECESS FOR SECURING THE CORRESPONDING EXTREMITIES OF SAID BANDS TO SAID HOUSING WITH SAID EXTREMITIES LYING SUBSTANTIALLY IN A COMMON PLANE PARALLEL TO SAID SURFACE, THREE BEATER BANDS BEING PROVIDED WITHIN SAID RECESS AND THE MOUTH OF SAID RECESS HAS SUBSTANTIALLY A WIDTH AT MOST EQUAL TO THE COMBINED WIDTHS OF SAID BANDS, SAID BANDS INCLUDING A PAIR OF OUTER BANDS AND A CENTRAL BAND DISPOSED BETWEEN SAID OUTER BANDS, SAID FORMATION BEING ENGAGEABLE WITH ONE OF SAID OUTER BANDS, SAID FASTENING MEANS BEING PROVIDED WITH A DEFLECTING MEMBER AT EACH EXTREMITY OF SAID CENTRAL BAND FOR RETAINING SAID CENTRAL BAND IN A MEAN POSITION THEREOF ABOVE SAID OUTER BANDS OVER SUBSTANTIALLY THE ENTIRE LENGTH OF SAID CENTRAL BAND. 